diff --git a/contracts/interfaces/IReward.sol b/contracts/interfaces/IReward.sol
index 1f66bee..453bcea 100644
--- a/contracts/interfaces/IReward.sol
+++ b/contracts/interfaces/IReward.sol
@@ -3,7 +3,12 @@
 pragma solidity >=0.8.0 <0.9.0;
 
 interface IReward {
-    event DistributeReward(uint indexed pricingIndex, address indexed beneficiary, uint amount);
+    event DistributeReward(
+        uint indexed pricingIndex,
+        address indexed beneficiary,
+        bytes32 indexed minerId,
+        uint amount
+    );
 
     function fillReward(uint beforeLength, uint rewardSectors) external payable;
 
diff --git a/contracts/miner/Mine.sol b/contracts/miner/Mine.sol
index 8f1d5f9..ae71e66 100644
--- a/contracts/miner/Mine.sol
+++ b/contracts/miner/Mine.sol
@@ -224,7 +224,7 @@ contract PoraMine is ZgInitializable, AccessControlEnumerable {
             uint scaledTarget = poraTarget >> 16;
             scaledExpected = Math.mulDiv(scaledTarget, targetMineBlocks, currentSubmissions);
         } else {
-            scaledExpected = type(uint).max >> 16;    
+            scaledExpected = type(uint).max >> 16;
         }
 
         _adjustDifficultyInner(scaledExpected);
@@ -235,7 +235,7 @@ contract PoraMine is ZgInitializable, AccessControlEnumerable {
     }
 
     function _adjustDifficultyInner(uint scaledExpected) internal {
-        if(fixedDifficulty) {
+        if (fixedDifficulty) {
             return;
         }
         uint scaledTarget = poraTarget >> 16;
@@ -327,13 +327,13 @@ contract PoraMine is ZgInitializable, AccessControlEnumerable {
         if (block.number <= subtaskMineStart || block.number - subtaskMineStart > targetMineBlocks) {
             return answer;
         }
-        
+
         answer.subtaskDigest = keccak256(abi.encode(answer.context.digest, blockhash(subtaskMineStart)));
 
         if (answer.context.epoch > lastMinedEpoch) {
             _updateMineEpochWhenNeeded(answer.context);
         }
-        
+
         if (currentSubmissions < targetSubmissions * 2) {
             answer.poraTarget = poraTarget;
         }
diff --git a/contracts/miner/MineLib.sol b/contracts/miner/MineLib.sol
index 7748d6e..1396d23 100644
--- a/contracts/miner/MineLib.sol
+++ b/contracts/miner/MineLib.sol
@@ -45,7 +45,7 @@ library MineLib {
         bytes32[UNITS_PER_SEAL] memory sealedData,
         uint skipSeals,
         bytes32[2] memory padDigest
-    ) internal view returns (bytes32[2] memory recallSeed, bytes32[UNITS_PER_SEAL] memory mixedData) {
+    ) internal pure returns (bytes32[2] memory recallSeed, bytes32[UNITS_PER_SEAL] memory mixedData) {
         bytes32[2] memory currentDigest = padDigest.deepCopy();
 
         scratchPadHash(currentDigest, skipSeals * BHASHES_PER_SEAL);
@@ -81,6 +81,7 @@ library MineLib {
         bytes32[8] memory slots;
         uint offset = 128;
         uint finalizeOffset = 128 + UNITS_PER_SEAL * 32;
+        bool blake2bError = false;
 
         assembly {
             let argPtr := add(slots, 0x1c)
@@ -100,7 +101,7 @@ library MineLib {
 
             for {
 
-            } lt(offset, finalizeOffset) {
+            } and(lt(offset, finalizeOffset), not(blake2bError)) {
 
             } {
                 offset := add(offset, 0x80)
@@ -118,10 +119,11 @@ library MineLib {
                 }
 
                 if iszero(staticcall(not(0), 0x09, argPtr, 0xd5, hPtr, 0x40)) {
-                    revert(0, 0)
+                    blake2bError := true
                 }
             }
         }
+        require(!blake2bError, "blake2b internal error at PoRA hash");
         // The blake2b hash locates at slots[1] and slots[2].
         // Here we only return the first 32 bytes of the blake2b hash.
         return slots[1];
diff --git a/contracts/miner/WorkerContext.sol b/contracts/miner/WorkerContext.sol
index ee47528..b973f9c 100644
--- a/contracts/miner/WorkerContext.sol
+++ b/contracts/miner/WorkerContext.sol
@@ -8,4 +8,4 @@ struct WorkerContext {
     uint poraTarget;
     bytes32 subtaskDigest;
     uint64 maxShards;
-}
\ No newline at end of file
+}
diff --git a/contracts/reward/ChunkRewardBase.sol b/contracts/reward/ChunkRewardBase.sol
index e9c2585..158ce9b 100644
--- a/contracts/reward/ChunkRewardBase.sol
+++ b/contracts/reward/ChunkRewardBase.sol
@@ -78,7 +78,7 @@ abstract contract ChunkRewardBase is IReward, PullPayment, ZgInitializable, Acce
         }
     }
 
-    function claimMineReward(uint pricingIndex, address payable beneficiary, bytes32) external {
+    function claimMineReward(uint pricingIndex, address payable beneficiary, bytes32 minerID) external {
         require(_msgSender() == mine, "Sender does not have permission");
 
         Reward memory reward = rewards[pricingIndex];
@@ -95,7 +95,7 @@ abstract contract ChunkRewardBase is IReward, PullPayment, ZgInitializable, Acce
 
         if (rewardAmount > 0) {
             _asyncTransfer(beneficiary, rewardAmount);
-            emit DistributeReward(pricingIndex, beneficiary, rewardAmount);
+            emit DistributeReward(pricingIndex, beneficiary, minerID, rewardAmount);
         }
     }
 
diff --git a/contracts/reward/OnePoolReward.sol b/contracts/reward/OnePoolReward.sol
index 2e4554f..1194e18 100644
--- a/contracts/reward/OnePoolReward.sol
+++ b/contracts/reward/OnePoolReward.sol
@@ -119,7 +119,7 @@ contract OnePoolReward is IReward, Context, ZgInitializable {
         }
     }
 
-    function claimMineReward(uint pricingIndex, address payable beneficiary, bytes32) external {
+    function claimMineReward(uint pricingIndex, address payable beneficiary, bytes32 minerID) external {
         require(_msgSender() == mine, "Sender does not have permission");
 
         if (pricingIndex < firstValidChunk) {
@@ -136,7 +136,7 @@ contract OnePoolReward is IReward, Context, ZgInitializable {
 
         if (claimable > 0) {
             beneficiary.transfer(claimable);
-            emit DistributeReward(pricingIndex, beneficiary, claimable);
+            emit DistributeReward(pricingIndex, beneficiary, minerID, claimable);
         }
     }
 
diff --git a/contracts/utils/Blake2b.sol b/contracts/utils/Blake2b.sol
index 0cf815c..a51f294 100644
--- a/contracts/utils/Blake2b.sol
+++ b/contracts/utils/Blake2b.sol
@@ -85,11 +85,13 @@ library Blake2b {
         bytes8[2] memory t = blake2bLength(offset);
         bytes memory args = abi.encodePacked(rounds, h[0], h[1], m0, m1, m2, m3, t[0], t[1], finalize);
 
+        uint blake2bOut;
+
         assembly {
-            if iszero(staticcall(not(0), 0x09, add(args, 32), 0xd5, output, 0x40)) {
-                revert(0, 0)
-            }
+            blake2bOut := staticcall(not(0), 0x09, add(args, 32), 0xd5, output, 0x40)
         }
+
+        require(blake2bOut != 0, "blake2b internal error at blake2bF");
     }
 
     function blake2bLength(uint length) internal pure returns (bytes8[2] memory t) {